The present invention relates to the preparation of zinc oxide (zincite) nanoparticle sol, particularly to the use of wet chemical process to prepare zinc oxide (zincite) nanoparticle sol having high concentration and high visible light transmittance, wherein the process uses only inorganic reactants and high boiling solvent so that volatile organic vapor or organic waste are avoid.
Zinc oxide (zincite, ZnO) is an odorless solid of hexagonal crystal structure, which can be used as white pigment, catalyst, antibacterial skin-protection ointment, sunscreen ointment, rubber vulcanization accelerator and ultraviolet absorber for woodwork vanishes.
The term “nanoparticle” refers to particles having a diameter smaller than 100 nm. Particles, particle aggregates or particle agglomerates of zinc oxide that are larger than about 30 nm lead to light scattering and thus become non-transparent in the visible light range. On the other hand, nanoparticles smaller than about 30 nm is transparent in visible light range, and are potentially suitable for use as UV absorbers in transparent organic-inorganic hybrid materials, transparent plastics, paints, coatings and for the protection of UV-sensitive organic pigments.
When zinc oxide is in nanoparticle form, its high specific surface area as well as the quantum size effect may further alter its magnetism, light, electric properties and increases its catalytic activity, thus offers possible applications in infrared, ultra violet ray resistance, sun-proof cosmetics, antibacterial and malodor resistance, photocatalyst and self-cleaning glass etc. Even in the rubber vulcanization accelerator application, a reduced formulation may be possible if nanocrystals of zinc oxide is used instead of the conventional zinc oxide particles.